The ratio of red blood cell distribution width to serum calcium predicts severity of patients with acute pancreatitis

Background: Illness severity of patients with acute pancreatitis (AP) at early stage is crucial because the identified moderate and severe cases need early intensive care to reduce the risk of serious complications such as multi-organ failure. Although red blood cell distribution width(RDW)and serum calcium(Ca)alone can be used as predictors of the severity of AP, they have low sensitivity and specificity. Thus, this study is aimed at evaluating the value of the ratio of RDW to serum calcium, which can all be acquired on admission, in predicting the severity of AP.

Methods: This study was based on a retrospective cohort study on patients with AP at the emergency department (ED) of West China Hospital Hospital from January 2016 to June 2016. We divided the patients with AP into two groups, mild acute pancreatitis (MAP) and moderate severe acute pancreatitis (MSAP) + severe acute pancreatitis (SAP). A receiver-operating characteristic (ROC) curve analysis was used to valuate the predictive value of the ratio of RDW to serum calcium for the severity of AP patients and the cut-off value for the ratio of RDW to serum calcium was calculated with sensitivity and specificity. P < 0.05 was considered statistically significant.

Results: A total of 666 AP patients were enrolled in this study. These patients were divided into MAP (n = 518) and MSAP+SAP (n = 148) groups. The AUC of RDW/ Ca was 0.912 (95% CI 0.887 to 0.937, P < 0.001), larger than the AUCs of RDW (AUC = 0.768, 95% CI 0.723 to 0.812, P < 0.001) and Ca (AUC = 0.875, 95% CI 0.844 to 0.906, P < 0.001). The optimal cut-off value for RDW/ Ca to predict MSAP and SAP was 7.04 (sensitivity = 0.885, specificity = 0.834).

Conclusion: The RDW/Ca might be a valuable predictor of the severity of patients with AP.